Dentistry tool

ABSTRACT

A drill bit and method for normalizing bone is provided. The drill bit has a non-round drill bit core that is adapted to cut hard bone and to not cut soft bone. The drill bit has a cutting edge which may be positioned within a compression zone of the non-round drill bit core. The rotational speed of the drill bit and the profile of the drill bit core are tuned so that hard bone recovers into a cutting zone defined by the cutting edge while soft bone remains outside of the cutting zone. The insertion torque of the drill bit can be measured to determine when the normalization is adequate.

This application is continuation of U.S. patent application Ser. No.16/073,281, filed Jul. 26, 2018, which is a national stage applicationunder 35 U.S.C. § 371 of International Application No.PCT/EP2017/051956, filed on Jan. 30, 2017, which published in English asWO 2017/129828 A1 on Aug. 3, 2017, and which claims priority benefit ofEP Patent Application No. 16153496.1, filed on Jan. 29, 2016, theentireties of these applications are hereby incorporated by referenceherein and made a part of the present disclosure.

FIELD

The present disclosure relates generally to a drill bit that can be usedin surgery and, in certain embodiments, to drill bits used in dentalsurgery or to a tool to enlarge an osteotomy.

DESCRIPTION OF THE RELATED ART

Holes are often formed in the jaw bones of patients in variouscircumstances and implantation situations. It is known that properpreparation of an implant-receiving hole can be important to achievingosseointegration and long-term success of the dental implant. Given thatthe density, orientation and quality of bone can differ from patient topatient, it is often necessary to use multiple tools and/or to havedifferent drilling protocols available to prepare the implant-receivinghole according to the density, orientation and quality of the patient'sjawbone. For example, depending upon the density of the bone at theimplantation site, a different set of tools and/or drill protocols canbe used to remove high-density bone from the hole as compared to animplantation site with low-density bone.

SUMMARY

The systems, methods and devices described herein have innovativeaspects, no single one of which is indispensable or solely responsiblefor their desirable attributes. Without limiting the scope of theclaims, some of the advantageous features will now be summarized.

One aspect of the disclosure herein is the recognition that there is aneed to simplify and improve the hole formation function so that fewerdrilling stages and/or protocols are needed and so that the result ofthe hole formation is still satisfactory. Another aspect of thedisclosure herein is the recognition that it would be advantageous thenumber of instruments and drills can be reduced without compromising theprecision of the hole formation across a range of bone quality, densityand/or orientation situations.

In a first aspect, an object of the invention is a drill bit comprising:

-   an apical end, a coronal end, and a longitudinal axis extending    between the apical end and the coronal end;    -   a drill bit core circumferentially surrounding the longitudinal        axis and having at least a portion with a non-round or        non-circular profile when viewed in a plane perpendicular to the        longitudinal axis, the portion with a non-round or non-circular        profile forming at least one first compression zone;    -   a first cutting edge; and    -   a guide thread which extends radially outward from the drill bit        core.

The first cutting edge may be disposed within the first compression zoneof the drill bit core.

The first cutting edge may be a first radial distance from thelongitudinal axis and a maximum outer dimension of the drill bit coremay be a second radial distance from the longitudinal axis. The secondradial distance may be larger than the first radial distance. Theextremity of the first radial distance may be different than theextremity of the second radial distance. The extremity of the firstradial distance may be at a different angular position than theextremity of the second radial distance. In other words, the firstcutting edge may be at a different angular position than a maximum outerdimension of the drill bit core.

In a second aspect, an object of the invention is a drill bitcomprising:

-   -   an apical end, a coronal end, and a longitudinal axis extending        between the apical end and the coronal end;    -   a drill bit core circumferentially surrounding the longitudinal        axis and having at least a portion with a non-round or        non-circular profile when viewed in a plane perpendicular to the        longitudinal axis, the portion with a non-round or non-circular        profile forming at least one first compression zone; and    -   a first cutting edge disposed within the first compression zone        of the drill bit core,    -   wherein the first cutting edge is a first radial distance from        the longitudinal axis and a maximum outer dimension of the drill        bit core is a second radial distance from the longitudinal axis,        the second radial distance being larger than the first radial        distance.

The drill bit may further comprise a guide thread which extends radiallyoutward from the drill bit core.

The drill bit according to the invention can comprise the followingfeatures taken alone or in combination:

-   -   the drill bit core is oval-shaped;    -   the drill bit core tapers toward the apical end;    -   the drill bit core comprises a maximum outer dimension that        circumferentially shifts about the longitudinal axis as the        drill bit core extends toward the apical end;    -   the non-round or non-circular profile is tri-lobed or tri-oval;    -   the drill bit core further comprises a second cutting edge        disposed within a second compression zone;    -   the drill bit core further comprises a cutting flute;    -   the cutting flute wraps circumferentially around the        longitudinal axis as the cutting flute extends between the        apical end and the coronal end of the drill bit; the cutting        flute may start at the coronal end of the drill bit; the cutting        flute may not extend to the apical end of the drill bit; the        cutting flute may not be present in at least a portion, e.g., in        at least the most apical portion, of the apical end of the drill        bit; the cutting flute may not be present at the entire apical        end of the drill bit; the first cutting edge is a first radial        distance from the longitudinal axis and a maximum outer        dimension of the drill bit core is a second radial distance from        the longitudinal axis, the drill bit core having a no-cutting        zone defined as the difference between the second radial        distance and the first radial distance;    -   the no-cutting zone remains constant between the apical and        coronal ends of the drill bit.

The guide thread may have a height that is defined as the distance theguide thread extends radially away from the drill bit core. The heightof the guide thread may be in the range of between 0 and 1000 μm,between 0 and 500 μm, or between 50 and 250 μm. In particular, theheight of the guide thread may be 300 μm.

The guide thread may have a width of 250 μm or less, 200 μm or less, or150 μm or less.

The guide thread may have a pitch of 1 mm or less.

The guide thread may have a substantially round profile, e.g., asubstantially circular profile, when viewed in a plane perpendicular tothe longitudinal axis.

The width of the guide thread may be different from the width of thecutting flute. The height of the guide thread may be different from theheight of the cutting flute. The pitch of the guide thread may bedifferent from the pitch of the cutting flute.

The cutting flute may have an opening with an angular length in therange of between 50° and 70°. The angular length of the opening of thecutting flute may be 60°.

In a third aspect, an object of the invention is a method of preparingan osteotomy, the method comprising:

-   -   drilling a hole in a jaw bone with a non-round or non-circular        drill bit.

The method can further comprise the following steps taken alone or incombination:

-   -   measuring an insertion torque of the drill bit during the        drilling step.    -   evaluating whether the insertion torque is within an acceptable        range.    -   stopping the drilling if the insertion torque is within an        acceptable range; and using a second drill bit to modify the        hole and repeating the measuring and evaluating step.

In a fourth aspect, an object of the invention is a method of implantingan implant into a jaw bone comprising:

-   -   drilling a hole in a jaw bone with a non-round or non-circular        drill bit; and    -   implanting an implant into the hole.

The method can further comprise the following steps of:

-   -   measuring an insertion torque of the drill bit during the        drilling step;    -   evaluating whether the insertion torque is within an acceptable        range;    -   installing an implant if the insertion torque is within an        acceptable range; and    -   modifying the hole and repeating the measuring and evaluating        step if the insertion torque is not within an acceptable range.

In a fifth aspect, an object of the invention is a kit of partscomprising a drill bit of the first aspect or the second aspect and animplant, in particular a dental implant.

The implant may comprise a thread. The drill bit may comprise a guidethread which extends radially outward from the drill bit core. The guidethread may differ from the thread of the implant in pitch and/or heightand/or width.

BRIEF DESCRIPTION OF THE DRAWINGS

Throughout the drawings, reference numbers can be reused to indicategeneral correspondence between reference elements. The drawings areprovided to illustrate example embodiments described herein and are notintended to limit the scope of the disclosure.

FIG. 1 shows an implant-receiving hole being prepared in a jaw bone.

FIG. 2 shows a panel of tools that can be used to prepare a hole in ajaw bone.

FIG. 3A is a side view of an embodiment of a drill bit.

FIG. 3B is a transverse cross-sectional view of the drill bit of FIG.3A.

FIGS. 4A-4D are perspective views of illustrative embodiments of a drillbit.

FIG. 5A is a side view of an embodiment of a drill bit.

FIG. 5B is a transverse cross-sectional view of the embodiment of FIG.5A.

FIG. 5C is an apical end view of the embodiment of FIG. 5A.

FIG. 6 is a transverse cross-sectional view of an embodiment of a drillbit.

FIGS. 7A-7D are transverse cross-sectional views of illustrativeembodiments of a drill bit.

FIGS. 8A-8C are side views of illustrative embodiments of a drill bit.

FIG. 9 is a side view of an embodiment of a drill bit.

FIG. 10 is a schematic representation of a method of implanting animplant into a bone.

FIG. 11 is a schematic representation of another method of implanting animplant into a bone.

DETAILED DESCRIPTION

Embodiments of systems, components and methods of assembly andmanufacture will now be described with reference to the accompanyingfigures, wherein like numerals refer to like or similar elementsthroughout. Although several embodiments, examples and illustrations aredisclosed below, it will be understood by those of ordinary skill in theart that the inventions described herein extends beyond the specificallydisclosed embodiments, examples and illustrations, and can include otheruses of the inventions and obvious modifications and equivalentsthereof. The terminology used in the description presented herein is notintended to be interpreted in any limited or restrictive manner simplybecause it is being used in conjunction with a detailed description ofcertain specific embodiments of the inventions. In addition, embodimentsof the inventions can comprise several novel features and no singlefeature is solely responsible for its desirable attributes or isessential to practicing the inventions herein described.

Certain terminology may be used in the following description for thepurpose of reference only, and thus are not intended to be limiting. Forexample, terms such as “above” and “below” refer to directions in thedrawings to which reference is made. Terms such as “front,” “back,”“left,” “right,” “rear,” and “side” describe the orientation and/orlocation of portions of the components or elements within a consistentbut arbitrary frame of reference which is made clear by reference to thetext and the associated drawings describing the components or elementsunder discussion. Moreover, terms such as “first,” “second,” “third,”and so on may be used to describe separate components. Such terminologymay include the words specifically mentioned above, derivatives thereof,and words of similar import.

FIG. 1 depicts an example traditional dental drill bit 10 drilling ahole 20 into a jaw bone 30 in order to prepare the jaw bone 30 forreceiving a dental implant. Long-term success of a dental implant candepend on proper preparation of the implant site. For example, thetorque required to advance the implant into the jaw bone 30 (alsoreferred to as “insertion torque”) can serve as an indication of initialstability of the implant. Implant stability can be an important factorfor implant osseointegration and immediate loading. Given that the jawbone 30 can consist of different bone types and/or each patient may havea jawbone of different quality, orientation and/or density, the methodof preparing the jaw bone 30 to receive an implant may need to betailored according to the density, orientation and/or quality of thebone at the site of implantation. For example, failure to remove asufficient amount of bone from an implant site having high-density bonecan result in a high insertion torque, which can harm the surroundingbone. Removing too much bone from an implant site having low-densitybone can result in a low insertion torque, which can be indicative thatimplant micro-motion will frustrate osseointegration.

FIG. 2 illustrates a traditional method of preparing the jaw bone 30 toreceive a dental implant that employs relatively complex drill protocolswith multiple steps and decisions, especially for dense bone situations.For example, a dense bone drilling protocol may include up to sevendrills and taps, including: a precision drill 11, a 2-mm-diametertapered drill 13, a first direction indicator 15, a 3.5-mm-diametertapered drill 17, a 4.3-mm-diameter tapered drill 19, a 5.0-mm-diametertapered drill 21, a second direction indicator 23, a 5.0-mm-diameterdense bone drill 25, and a 5.0-mm-diameter screw tap tapered drill 27.Dental implant manufacturers provide guidelines on which combination oftools to use, in which bone quality situations, to achieve the desiredinsertion torques. In some situation, a clinician must first estimatelocal bone quality before choosing which drill protocol to follow. Ifthe estimation of bone quality is incorrect, the chosen drill protocolmay also be incorrect, which can lead to an insertion torque that is toohigh or too low.

One aspect of the present disclosure is the recognition that in regionshaving low-density bone, insertion torques can be improved by leavingthe low-density bone in place. Moreover, in regions of high-densitybone, it can be desired to remove the high-density bone from the site ofimplantation in order to make room for the incoming implant.Accordingly, it would be advantageous to have an instrument and/ormethod that can selectively cut away high-density bone from the implantsite while leaving low-density bone in place. Such an instrument and/ormethod may also advantageously simplify drill protocol procedures.

FIG. 3A shows a non-limiting, illustrative embodiment of a drill bit 100having certain features and advantages of the present disclosure. Thedrill bit 100 can have a longitudinal axis 102, an apical end 104, and acoronal end 106. In the illustrated embodiment, the drill bit 100 istapered so that the outer dimension of the drill bit 100 decreases asthe drill bit 100 extends toward the apical end 104, as shown in FIG.3A. In some variants and embodiments, the drill bit 100 is not tapered.For example, in some embodiments, the outer dimension of the drill bit100 can remain substantially constant as the drill bit 100 extendstoward the apical end 104. The drill bit 100 can also include anattachment 110 by which the drill bit 100 can connected to a drillingmachine (not shown) and/or handle (not shown). The attachment 110 can beat the coronal end 106 of the drill bit 100 and can be in certainembodiments coupled to the drill bit 100 and/or formed integrally withthe drill bit 100. The drill bit 100 can be rotated about thelongitudinal axis 102 as described below to form a hole in a patient'sjawbone.

With continued reference to FIG. 3A, the drill bit 100 can have a guidethread 113 that extends radially outward from a drill bit core 120 ofthe drill bit 100. In the illustrated embodiment, drill bit core 120 istapered so that the outer dimension of the drill bit core 120 decreasesas the drill bit 100 extends toward the apical end 104. As with thedrill bit 100, in other embodiments, the drill bit core can havesubstantially cylindrical or taper in a different manner. In theillustrated embodiment, the guide thread 113 is not a working tap but isinstead configured to guide the drill bit 100 in and out of the bone ina controlled manner while allowing measurement of the insertion torqueto determine the bone quality. In this way, the guide thread 113 can aidin providing an objective measurement of bone quality and thereby reduceerror that may arise from a subjective determination of the clinicianregarding bone quality. The guide thread 113 controls the insertionspeed relative to the number of revolutions of the drill bit 100. Thefull insertion of the drill bit 100 in the bone is reached after aconstant number of revolutions and therefore, after full insertion, themaximum torque measured by the drill unit or a torque wrench is directlyrelated to the average bone quality over the length. The decision to useone drilling protocol over another can be based on the insertion torqueof the drill bit 100. For example, if the insertion torque is below acertain level, the clinician may elect to use a drilling protocol thatis designed for low-density bone. If the insertion torque is above acertain level, the clinician may elect to use a drilling protocol thatis designed for high-density bone. In another embodiment, if theinsertion torque of the drill bit 100 is below a certain level, the fullinsertion depth may not be needed (for example in case of soft bone),thus creating a shorter and smaller osteotomy. This would be the case inlow quality or softer bone. For a human being, the bone density may varyfrom 16 g/cm3 (soft bone) to 80 g/cm3 (hard bone). In hard bone, thetool would be used to the full depth, thus creating a longer and largerosteotomy.

The guide thread 113 can be adapted to allow the drill bit 100 to beadvanced into the bone in a controlled fashion, at a low speed (e.g.,about 10-100 rpm), without irrigation, or a combination thereof.Low-speed drilling can generate less heat than high-speed drilling,making low-speed drilling potentially less harmful to the bone tissuethan high-speed drilling. Drilling methods that avoid irrigation canhave biological benefits for bone healing by not removing (e.g.,washing) bone chips and blood out of the osteotomy.

FIG. 3B shows a transverse cross-sectional view of the drill bit core120 of the drill bit 100 taken a point along the longitudinal axis 102of the drill bit 100. For the sake of clarity, the guide thread 113 isnot shown on the outer surface of the drill bit core 120 in thecross-sectional view. The drill bit core 120 can have a non-round ornon-circular cross-sectional shape along a length l (in the longitudinaldirection) of the drill bit 100 with the cross-sectional shape beingtaken along a plane that is generally perpendicular to the longitudinalaxis 102 of the drill bit 100 as shown in FIG. 3A. In one embodiment,the drill bit core 120 has a non-round cross-sectional shape over theentire length of the drill bit core 120 (or of the portion of the drillbit 100 intended to be in contact with the bone) and in certainembodiments, the non-round cross-sectional shape can extend over 50 to90% of the length of the drill bit core 120. In the illustratedembodiment, the shape of non-round cross-sectional shape of the drillbit core 120 can remain generally constant over the length of the drillbit core 120. For example, in an embodiment in which the drill bit core120 tapers such that the outer dimension of the drill bit core 120decreases as the drill bit 100 extends toward the apical end 104, thenon-round cross-sectional shape of the drill bit core 120 can remaingenerally constant while changing in dimensions. In other embodiments,the drill bit core 120 can have more than one non-round cross-sectionalshape over the length of the drill bit core 120.

The drill bit core 120 can have a minimum radius 202 and a maximumradius 204. The drill bit 100 can be rotated about the longitudinal axis102, as indicated in FIG. 3B by the semi-circular arrow 201. As thedrill bit 100 is rotated about the longitudinal axis 102, the minimumradius 202 will sweep out an inner circle 212, and the maximum radius204 will sweep out an outer circle 214. Accordingly, a reference pointon the surrounding bone will be pushed radially outward as the maximumradius 204 approaches the reference point. The reference point can reacha maximum displacement 301 when the maximum radius 204 arrives at thereference point. After the maximum radius 204 passes the referencepoint, the reference point can move radially inward to occupy the spacevacated by the rotating drill bit 100. The reference point can reach aminimum displacement 301′ when the minimum radius 202 arrives at thereference point. In this way, the surrounding bone can move back andforth across a working margin 302, as indicated by the double-headedarrow in FIG. 3B.

The drill bit 100 can form a compression zone 220 corresponding to theregion of the drill bit 100 that compresses the surrounding bone. Forexample, in the illustrative embodiment shown in FIG. 3B (in which thedrill bit 100 is rotating in the clockwise direction), the compressionzone 220 extends from the maximum radius at the twelve o'clock positionof the drill bit core 120 to the minimum radius at the two o'clockposition of the drill bit core 120. The drill bit 100 can have adecompression zone 222 corresponding to the region of the drill bit 100that allows decompression of the surrounding bone. For example, in theillustrative embodiment shown in FIG. 3B, the decompression zone 222 canextend from the minimum radius at the two o'clock position of the drillbit core 120 to the maximum radius at the four o'clock position of thedrill bit core 120. In some variants, the drill bit 100 can include morethan one compression zones 220 and decompression zones 222. For example,the tri-oval embodiment of FIG. 3B has three compression zones 220 andthree decompression zones 222. Modified embodiments can include more orless compression zones and/or three compression zones with differentshapes. Moreover, as noted above, the drill bit core 120 can haveregions in which the non-round cross-sectional shape of the drill bitcore 120 can be different or change. In addition, in the illustratedembodiment tri-oval embodiment includes three compression anddecompression zones that have similar dimensions that fluctuate from thesame maximum radius to minimum radius. However, in modified embodiments,the compression and decompression zones can fluctuate from maximum radiito minimum radii of different dimensions such that a different amount ofcompression and/or decompression occurs in each zone.

An aspect of certain embodiments of the disclosure is the recognitionthat the surrounding bone can have a recovery time defined as the timerequired for the surrounding bone to move from the maximum displacement301 to the minimum displacement 301′. The recovery time of thesurrounding bone can depend on the quality of the bone. For example,hard bone can have a shorter recovery time compared to soft bone. Thus,hard bone will tend to move more quickly from the maximum displacement301 to the minimum displacement 301′ than will soft bone. As discussedbelow, the drill bit 100 can be adapted to exploit the difference inrecovery times between the hard and soft bone so that the drill bit 100can selectively cuts hard bone while leaving soft bone intact ordisproportionately cut hard bone as compared to softer bone.

The drill bit core 120 can include a cutting flute 230. The cuttingflute 230 can have a cutting edge 232 and a trailing edge 234. Thecutting edge 232 can be a cutting distance 233 from the longitudinalaxis 102, which will be equal to the radius or rotation of the cuttingedge 232. The trailing edge 234 can be a trailing distance 235 from thelongitudinal axis 102, which will be the radius of rotation of thetrailing edge 234. The cutting flute 230 can be positioned in thecompression zone 220, as illustrated in FIG. 3B. Referring to FIG. 3B,by positioning the cutting flute 230 in the compression zone 220, thecutting distance 233 can be larger than the trailing distance 235.

The cutting edge 232 can be positioned within the working margin 302, asillustrated in FIG. 3B. In other words, the cutting distance 233 can beintermediate to the maximum displacement 301 and minimum displacement301′ of the surrounding bone. The cutting edge 232 can sweep out acutting circle 213 that can be interposed between the inner and outercircles 212, 214 that are swept out by the minimum and maximum radii ofthe drill bit core 120. The region between the outer circle 214 and theintermediate circle 213 represents a “no-cutting” zone because bone inthis region will not encounter the cutting edge 232 as the cutting edge232 passes by the bone. In some embodiments, the width of the“no-cutting” zone can be about 50 μm. The region between theintermediate circle 213 and the inner circle 212 represents a “cutting”zone because bone in this region will be cut by the cutting edge 232 asthe cutting edge 232 passes by the bone.

The circumferential placement of the cutting edge 232 and the rotationalspeed of the drill bit 100 can be adjusted so that as the cutting edge232 passes by the bone, the hard bone has had sufficient time to enterthe “cutting” zone while the slower recovering soft bone remains in the“no-cutting” zone. A rotation time (RT) can be defined as the timeneeded for the cutting edge 232 to travel the distance between thecutting edge 232 and the preceding maximum of the drill bit core 120.Referring to FIG. 3B, RT would be equal to the time needed for point Ato travel to line B. A soft bone recovery time (SBRT) can be defined asthe time needed for the soft bone to return from the outer circle 214 tothe intermediate circle 213. A hard bone recovery time (HBRT) can bedefined as the time needed for hard bone to return from the outer circle214 to the intermediate circle 213. The drill bit 100 and drill speed(e.g., rpm) can be tuned so that two criteria are met: (1) SBRT>RT,thereby avoiding cutting soft bone; and (2) HBRT<RT, thereby cuttinghard bone. Parameters that can be considered when designing the drillbit 100 include: the difference in recovery times between hard and softbone, the difference between the maximum radius of the drill bit core120 and the radius of the cutting edge 232, the circumferentialplacement of the cutting flute 230, the rotational speed of the drillbit 100, the rate of radial change of the outer surface of the drill bitcore 120, and the insertion speed of the drill bit 100.

Referring to FIGS. 4A-4B, the drill bit 100 of the present disclosurecan include different configurations of the drill bit core 120. Forexample, the drill bit 100 can include a plurality of tri-oval drill bitcores 120 that are interlinked in a helical configuration to form ascrew-like structure that extends to the apical end 104 of the drill bit100. The drill bit cores 120 of the illustrated drill bit 100 can taperin the apical direction. However, in some variants, the outer dimensionof the drill bit cores 120 can remain substantially constant along thelength of the drill bit 100.

As shown in FIG. 4A, in an embodiment, the cutting edges 232 of thedrill bit core 120 can be aligned with one another along a line 107 thatextends from the apical end 104 toward the coronal end 106 of the drillbit 100, thereby forming a straight or substantially straight cuttingflute 230 in which the line 107 extends generally parallel to thelongitudinal axis 102 of the drill bit 100. As shown in FIG. 4B, in somevariants, the cutting edges 232 of the drill bit core 120 can be alignedwith one another along a curve 109 that extends from the apical end 104toward the coronal end 106 of the drill bit 100, thereby forming acurved cutting flute 232. The drill bit core 120 can taper or can have asubstantially constant outer dimension along the length of the drill bit100. In the illustrated embodiment, the curve 109 bends generally in thesame direction of a helical thread on the drill bit core 120 (e.g.,counter-clockwise toward the coronal end 106). In some variants, thecurve 109 can bend generally in the direction opposite of the helicalthread of the drill bit cores 120.

Referring to FIG. 4C, the drill bit 100 can include a plurality ofplanar tri-oval drill bit cores 120 that are aligned substantiallyperpendicular to the longitudinal axis 102 of the drill bit. The planartri-oval drill bit cores 120 can be spaced apart from one another,thereby forming a gap 111 between adjacent planar tri-oval drill bitcores 120. In the illustrated embodiment, the drill bit cores 120 nearthe apical end 104 of the drill bit 100 have a smaller outer dimensionthan the drill bit cores 120 toward the coronal end 106 of the drillbit. In other words, the drill bit 100 tapers toward the apical end 104.However, in some variants, the outer dimension of the drill bit cores120 can remain substantially constant along the length of the drill bit100. In the illustrated embodiment, the cutting surfaces 232 of adjacentdrill bit cores 120 are circumferentially shifted relative to oneanother so that the cutting surfaces 232 lie along a curve 109, therebyforming a disjointed cutting flute 230 that spirals around the outersurface of the drill bit 100. In some variants, the cutting surfaces 232of the plurality of planar tri-oval drill bit cores 120 align with oneanother along a line, as described above with regard to FIG. 4A.

Referring to FIG. 4D, the maximum outer dimension of the drill bit core120 can taper and shift circumferentially in the apical direction in anuninterrupted manner, thereby producing a spiraling and continuouscutting flute 230. A spiraling cutting flute can facilitate removal ofcut material (e.g., bone chips) from the osteotomy, as discussed below.In the illustrated embodiment, the position of the cutting edge 232relative to the maximum outer dimension of the drill bit core 120remains substantially fixed along the length of the drill bit 100. Asshown in FIG. 4D, the trailing edge 234 can align along a curve 105 thatspirals around the longitudinal axis 102. The cutting edge 232 can alsoalign along a curve that is substantially parallel to the curve 105.

The drill bit 100 of the present disclosure can include variousconfigurations of the cutting edge 232 and of the maximum and minimumdimensions of the drill bit core 120. For example, the position of themaximum and minimum outer dimensions of the drill bit cores 120 can bealigned along the length of the drill bit, as shown in FIG. 4A. Incertain variants, the position of the maximum and minimum outerdimensions of the drill bit cores 120 can shift circumferentially alongthe length of the drill bit, as shown in FIG. 4C. The position of thecutting edge 232 relative to the maximum outer dimension of the drillbit cores 120 can remain constant along the length of the drill bit 100,as shown in FIG. 4A. The position of the cutting edge 232 can shifttoward or away from the maximum outer dimension of the drill bit core120. In some variants, both the position of the maximum outer dimensionof the drill bit cores 120 and the position of the cutting edge 232relative to the maximum outer dimension of the drill bit core 120 canshift circumferentially along the length of the drill bit 100. Moreover,the aforementioned variations of the drill bit core 120 can be achievedon a drill bit core 120 that is continuous along the length of the drillbit 100 (as in FIG. 4D) or on a drill bit core 120 that is discontinuous(as in FIG. 4C).

FIG. 5A is a non-limiting, illustrative embodiment of the drill bit 100having an oval-shaped drill bit core 120. FIG. 5B shows a cross-sectionof the drill bit core 120 along a plane that is perpendicular to thelongitudinal axis 102 of the drill bit 100. The maxima of theoval-shaped drill bit core 120 can be twisted in sync with the cuttingflute 230. The guide thread 113 can have a height that is defined as thedistance the guide thread 113 extends radially away from the drill bitcore 120. The guide thread 113 can have a substantially round profile,e.g., a substantially circular profile, while the core 120 can have anoval-shaped profile. Thus, the height of the guide thread 113 can varyalong the circumference of the drill bit core 120, with the height ofthe guide thread 113 being greatest at the minima of the oval-shapeddrill bit core 120 and the height of the guide thread 113 being least atthe maxima of the oval-shaped drill bit core 120.

FIG. 5C is an end view of the drill bit 100 from the apical end 104. Asshown in FIG. 5C, as the drill bit 100 tapers in the apical direction,the ovality of the drill bit core 120 can increase in the apicaldirection. The apical tip of the drill bit 100 can have the highesteccentricity. The eccentricity (ratio between the maximum and minimumradii of the drill bit core 120) is a consequence of the ovality, whichis the absolute difference between the maximum and minimum radii of thedrill bit core 120. In other words, the transverse cross-section of thedrill bit core 120 can be more round toward the coronal end 106 of thedrill bit 100 compared to the transverse cross-section of the drill bitcore 120 toward the apical end 104 of the drill bit 100. This is becausein some variants the working margin 302 (shown in FIG. 3B) can besubstantially constant along the length of a drill bit 100 that taperstoward the apical end 104. For example, in the illustrated embodiment,the working margin 302 can remain about 150 μm along the length of thedrill bit 100, while the outer diameter of the drill bit core 120 cantaper from about 4 mm at the coronal end 106 of the drill bit to about 2mm at the apical end 104 of the drill bit. At the apical tip, thecutting edge 232 can be at about 40° from the maximum radius of theoval-shaped drill bit core 120. In one embodiment, the eccentricity canvary over the full length of the drill bit core 120 such that it ishigher at the apical tip. In another embodiment, the apical tip has around shape at least on a portion of the length of the drill core 120 toallow insertion of the drill bit and because very little cutting occursat the tip. The eccentricity can increase after the round apical sectionand then decrease toward the coronal end. This round section can extend,for example up to 2 mm along the longitudinal axis of the implant fromthe apical end 104 of the drill bit.

Referring to FIG. 6 , the attack angle of the cutting edge 232 can bemodified to make the drill bit 100 more or less aggressive at cuttingthe surrounding bone. In the illustrated embodiment, the cutting edge232 forms and angle 238 of about 50° with the maximum radius 204 of thedrill bit core 120. In some embodiments, the angle 238 can be at leastabout: 10°, 20°, 30°, 40°, 50°, or otherwise. In certain variants, thecutting flute 230 can be made larger by moving the cutting edge 232 andtrailing edge 234 apart from one another. In some embodiments, thecutting flute 230 can be made large in order to accommodate bone chipsthat are cut by the cutting edge 232. In some variants, the drill bit100 can include a cavity 240 for collecting bone chips that are cut fromthe surrounding bone by the cutting edge 232. In other embodiments, thecutting edge can be placed on the maximum radii.

In the illustrated embodiment of FIG. 6 , the cutting edge 232 has beenpositioned near to the maxima of the drill bit core 120. As discussedabove, by positioning the cutting edge 232 closer to the maxima of thedrill bit core 120, RT can be increased because it can take longer forthe cutting edge 232 to arrive at the site of the bone that wascompressed by the preceding maxima. Also, by positioning the cuttingedge 232 closer to the maxima, the cutting distance 233 (shown in FIG.3B) can be enlarged. Enlarging the cutting distance 233 can reduce SBRTand HBRT because the distance from the maximum displacement 301 to thecutting zone is reduced. Thus, the combined effect of a longer RT and ashorter SBRT can result in more soft bone being cut by the drill bit100. Similarly, the combined effect of a longer RT and a shorter HBRTcan result in more hard bone being cut by the drill bit 100. Theillustrated drill bit 100 is an aggressive tri-oval drill bit 100 thatmay cut soft bone as well as hard bone, although the extent of hard bonecutting can be greater than the extent of soft bone cutting because hardbone will recover faster and therefore extend further into the cuttingzone than will the soft bone.

Referring to FIGS. 7A-7D, the drill bit core 120 of the drill bit 100can have different cross-sectional shapes. The cross-sectional shape ofthe drill bit core 120 can be configured to minimize cutting soft bone,minimize friction, minimize heat, and/or maximize directional control(e.g., avoid wobbling) or maximize cutting of hard bone. In theillustrated embodiments, the direction of rotation of the drill bit core120 is indicated by the arrow 210. FIG. 7A shows a drill bit core 120having a substantially rounded profile. The radial distance of thecutting edge 232 is substantially equal to the radial distance of thetrailing edge 234. In the shown embodiment, the drill bit core 120 hastwo cutting flutes 230 that are circumferentially spaced 180° apart fromone another. FIG. 7B shows an oval-shaped drill bit core 120 having twocutting flutes 230 that are circumferentially spaced 180° apart from oneanother, with the radial distance of the cutting edge 232 beingsubstantially equal to the radial distance of the trailing edge 234. Insome variants, the ovality of the drill bit 120 can be small asindicated by the dashed core 121. FIG. 7C shows a tri-oval drill bitcore 120 having three cutting flutes 230 circumferentially spaced about120° apart from an adjacent cutting flute 232. In the illustratedembodiment, the radial distance of the cutting edge 232 is substantiallyequal to the radial distance of the trailing edge 234. FIG. 7D depicts acruciform drill bit core 120 having four cutting flutes 230circumferentially spaced about 90° apart from an adjacent cutting flute232. In the illustrated embodiment, the radial distance of the cuttingedge 232 is substantially equal to the radial distance of the trailingedge 234. As shown in FIG. 7D, the drill bit core 120 can include one ormore protrusions 245. In some variants, the protrusion 245 can extendradially beyond the radial distance of the cutting edge 232 by about 50μm.

Referring to FIGS. 8A-8C, the drill bit 100 can have a variety ofmacro-shapes. The macro-shape of the drill bit 100 can be defined by theouter dimension of the drill bit core 120 along the longitudinal axis102 of the drill bit 100. The shape of the osteotomy will match themacro-shape of the drill bit 100 that was used to produce the osteotomy.Referring to FIG. 8A, the macro-shape of the drill bit 100 can betapered in the apical direction. The taper can be pointed or blunted.The taper can be constant along the length of the drill bit 100. Thetaper can vary along the length of the drill bit 100. For example, thetaper in some regions of the drill bit 100 may be steeper than in otherregions of the drill bit 100.

In some embodiments, the macro-shape of the drill bit 100 is selected tomatch the macro-shape of the implant. As shown in FIG. 8B, the drill bit100 can have an apical base 404 and a coronal base 406. The apical base404 is the apical-most surface of an apical portion 414, and the coronalbase 406 is the coronal-most surface of a coronal portion 416, as shownin FIG. 8B. In some variants, the coronal base 406 can have an outerdimension 405 that is greater than the outer dimension 403 of the apicalbase 404. For example, in the illustrated embodiment, the drill bit 100can have a coronal base 406 that has an outer dimension 405 of about 3.2mm wide and an apical base 404 that has an outer dimension 403 of about2 mm wide. The coronal portion 416 can taper in the apical directionwhile the apical portion has a substantially constant width. The coronalportion 416 can have a longitudinal length 409 and the apical portion414 can have a longitudinal length 407. In some embodiments, the coronalportion 416 has a longitudinal length 409 of about 13 mm and the apicalportion 414 has a longitudinal length 407 of about 2 mm.

Referring to FIG. 8C, the drill bit 100 can have an intermediate portion418 interposed between the coronal portion 416 and the apical portion414. In some embodiments, the drill bit 100 can have more than oneintermediate portion 418, as shown in the embodiment on the far right ofFIG. 8A. The intermediate portion 418 can have a coronal surface 420that is the coronal-most portion of the intermediate portion 418. In theembodiment depicted in FIG. 8C, the drill bit 100 can have a coronalbase 406 that has a width of about 3.8 mm, a coronal surface 420 that isabout 3.2 mm, and an apical base 404 that is about 2 mm. Thelongitudinal length of the coronal portion 416 can be about 12 mm, thelongitudinal length of the intermediate portion 418 can be about 1 mm,and the longitudinal length of the apical portion 414 can be about 2 mm.

FIG. 9 depicts a non-limiting, illustrative embodiment of the drill bit100 having a twisted and tapered oval drill bit core 120, as describedabove. In some variants, the cutting flute 230 can be adapted totransport cut bone out of the osteotomy. For example, in the illustratedembodiment, the cutting flute 230 has a spiral configuration at a pitchof about 45°. The pitch of the cutting flute 230 can be selected so thatbone chips do not get stuck in the cutting flute 230 and are transportedout of the osteotomy. In the illustrated embodiment, the cutting flute230 wraps in the direction of rotation of the drill bit 100, which isclockwise toward the apical end 104. This configuration can transportbone chips toward the coronal end 106 of the drill bit 100 and out ofthe osteotomy when the drill bit 100 is rotated in the direction forcutting bone. The depicted embodiment has guide threads 113 with a roundprofile. The guide threads 113 can be substantially perpendicular to thelongitudinal axis 102, as shown in FIG. 9 . In some variants, the guidethreads 113 can be angled toward the apical end 104 of the drill bit100. As the function of the guide threads 113 is only to control theinsertion of the tool and not cut a thread for the implant to besubsequently placed, the pitch of the guide thread does not match theone of the implant. This has the advantage that the user does not haveto be concerned about following the same thread path.

FIG. 10 depicts a schematic of an embodiment of a method of use of thedrill bit 100 of an embodiment of the present disclosure to prepare anosteotomy for receiving an implant. As discussed, the drill bit 100 canbe adapted to reduce the number of tools and/or steps needed to preparethe osteotomy. The procedure of preparing an osteotomy for receiving animplant may be referred to herein as “normalizing” the bone. The drillbit 100 can be adapted to normalize the bone with the use of only onedrill bit 100. In some variants, two or more drill bits 100 can be usedto normalize the bone. As shown in FIG. 10 , the method may include astep 600 in which a hole is drilled into the bone using a pilot drillbit that has a diameter smaller than the drill bit 100. In someembodiments, the pilot step 600 uses a pilot drill bit having a diameterof 2 mm. The pilot step 600 can be performed using irrigation. The drillspeed in step 600 can be about 800 rpm.

Still referring to FIG. 10 , the method of preparing the osteotomy forreceiving an implant can include a normalizing step 602. A first drillbit 100 according to an embodiment described herein can be used in thenormalizing step 602. The first drill bit 100 can be selected based onthe implant that will be implanted into the osteotomy. In some variants,the first drill bit 100 can be used to enlarge the hole created by adrilling step 600. In certain variants, the normalizing step 602 can beperformed without performing a preceding drilling step 600. Thenormalizing step 602 can be performed with or without irrigation. Thenormalizing step 602 can be performed using a drill speed of about 50 to100 rpm. In some variants, the normalizing step 602 can include ameasuring step 604 that determines the insertion torque. The measuringstep 604 can determine the insertion torque by sensing the torqueapplied to the drill bit 100. The measuring step 604 can include anevaluating step 606 that evaluates whether the normalization of the boneis successful. In some variants, the evaluating step 606 can compare anactual insertion torque as measured in the measuring step 604 with adesired insertion torque. The desired insertion torque can be determinedby a look-up table that correlates implant success to insertion torque.In some variants, the normalization can be adequate when the insertiontorque is less than or equal to about 40 Ncm. In some embodiments, thedesired insertion torque may be modified based on the type of implantthat is intended to be installed in the osteotomy.

The method of preparing the osteotomy for receiving an implant caninclude a further normalizing step 608. The further normalizing step 608can be performed using a second drill bit 100′ according to anembodiment described herein. The second drill bit 100′ can have adifferent macro-shape compared to the first drill bit 100. The seconddrill bit 100′ can have a different configuration of the drill bit core120 compared to the first drill bit 100. The method of preparing theosteotomy for receiving an implant can be iterative. For example, themethod can proceed from the further normalization step 608 to themeasuring step 604 and the evaluating step 606 multiple times until thenormalization is adequate to receive an implant.

In another embodiment during the normalization step 602 the torque ismeasured, by a drilling unit or controller connected to the drill bit100, at or until a predefined length of the drill bit 100 has beeninserted into the hole created by a drilling step 600. Said predefinedlength can be controlled mechanically, for example, the drill bit canhave a removable stop whose position is calibrated for soft boneindicating the maximum drilling length for the torque measurement.Alternatively, the predefined length can be controlled by a software ofthe drill unit measuring the torque. If the torque measured until or atsaid predefined length is above a certain value indicating the presenceof hard bone, then the drill unit can indicate to the user to continuedrilling beyond the predefined length. The removable stop can be removedand drilling resumes until a second fixed stop, whose position iscalibrated for hard bone. If the torque measured until or at saidpredefined length is below a certain value indicating the presence ofsoft bone the drill unit can indicate to the user to stop drilling andto start implanting an implant 620. Furthermore the drill unit can beprovided with a screen or any kind of user interface indicating to theuser the quality of the bone to help the decision. The type of bone canalso be indicated by the drilling unit to the user using and audiblesignal such as an alarm. Alternatively the drilling unit can directlycontrol the insertion depth based on the torque measured and stop thedrilling with first drill bit 100 after a specified number of turns.

The drill bit 100 of the present disclosure can be used in a method ofimplanting an implant into a jaw bone 30 (shown in FIG. 1 ). The methodof implanting an implant into a jaw bone 30 can include the method ofpreparing the osteotomy for receiving an implant described above. Themethod of implanting an implant into a jaw bone 30 can include aninstalling step 610. The installing step 610 can include implanting animplant 620 into an osteotomy prepared with the drill bit 100. Theinstalling step can be performed with or without irrigation. Theinstalling step 610 can be performed at a rotational speed of theimplant 620 of about 50 rpm. In some variants, the installing step 610can be performed at a rotational speed of the implant 620 of about 25rpm.

FIG. 11 is a schematic representation of another embodiment of a methodof use of the drill bit 100 of an embodiment of the present disclosureto prepare an osteotomy for receiving an implant. As is shown in FIG. 11, the method may include a pilot step 700 in which a hole is drilledinto the jaw bone 730 using a pilot drill bit that has a diametersmaller than the drill bit 100. The hole created in the pilot step 700serves as a guiding hole for the following steps. The hole created inthe pilot step 700 may be an underprepared site. The pilot step 700 canbe performed using irrigation. The drill speed in the pilot step 700 canbe about 800 rpm. For example, the pilot drill bit used in the pilotstep 700 may have a diameter in the range of 1.8 to 2.4 mm. In someembodiments, the pilot step 700 uses a pilot drill bit having a diameterof 2 mm.

Still referring to FIG. 11 , the method of preparing the osteotomy forreceiving an implant can include a first normalizing step 702. A firstdrill bit 100 according to an embodiment described herein can be used inthe first normalizing step 702. The first drill bit 100 can be selectedbased on the implant that will be implanted into the osteotomy. In somevariants, the first drill bit 100 can be used to enlarge the holecreated by the pilot step 700. In certain variants, the firstnormalizing step 702 can be carried out without performing a precedingdrilling step 700. The first normalizing step 702 can be performed withor without irrigation. The first normalizing step 702 can be performedusing a drill speed of about 50 to 100 rpm, in particular, using a drillspeed of about 50 rpm.

In particular, the first drill bit 100 may be configured such that thefirst cutting edge is a first radial distance from the longitudinal axisand a maximum outer dimension of the drill bit core is a second radialdistance from the longitudinal axis, wherein the second radial distanceis larger than the first radial distance. The drill bit core of thefirst drill bit 100 may have a no-cutting zone defined as the differencebetween the second radial distance and the first radial distance.

The method illustrated in FIG. 11 may comprise a first evaluating step704 in which it is evaluated whether the first drill bit 100 can befully inserted into the osteotomy in the first normalizing step 702. Inthis first evaluating step 704, it is determined whether the first drillbit 100 is properly inserted into the osteotomy, i.e., inserted along asufficient length of the first drill bit 100, and the torque applied tothe first drill bit 100 is measured. Based on the results of thisevaluation, i.e., on the results of determining the insertion length ordepth and of measuring the applied torque, the next steps are selected,as will be further detailed in the following.

For example, in order to determine whether the first drill bit 100 isproperly inserted, the first drill bit 100 may be provided with amarking, such as a shoulder, which indicates an insertion length of thefirst drill bit 100 that is equal or at least similar to the length ofthe implant 720 to be implanted into the osteotomy. If it is found that,in the first normalizing step 702, the first drill bit 100 has beeninserted into the osteotomy along such a length that the marking isarranged at the coronal end of the osteotomy, it is determined that thefirst drill bit 100 is inserted along a sufficient length.

The torque applied to the first drill bit 100 can be measured, forexample, by a drilling unit or a controller connected to the first drillbit 100, e.g., when or until a predefined length of the first drill bit100 has been inserted into the hole created in the pilot step 700. Insome variants, the first evaluating step 704 can compare an actualinsertion torque as measured in this step with a desired insertiontorque. The desired insertion torque can be determined by a look-uptable that correlates implant success to insertion torque. In somevariants, the normalization can be adequate when the insertion torque isless than or equal to about 40 Ncm. In some embodiments, the desiredinsertion torque may be modified based on the type of implant that isintended to be installed in the osteotomy.

If the first evaluating step 704 provides a positive result, i.e., aresult indicating that the first drill bit 100 has been inserted along asufficient length and the measured torque has a desired value, aninstalling step 706 is performed. In the installing step 706, theimplant 720 is inserted into the osteotomy prepared with the drill bit100. The installing step 706 can be performed with or withoutirrigation. The installing step 706 can be performed at a rotationalspeed of the implant 720 of about 50 rpm. In some variants, theinstalling step 706 can be performed at a rotational speed of theimplant 720 of about 25 rpm. In the installing step 706, the implant 720may be inserted into the jaw bone 730 under the application of aninsertion torque in the range of about 25 to 70 Ncm (see FIG. 11 ).

If the first evaluating step 704 provides a negative result, a secondnormalizing step 708 is performed. The second normalizing step 708 canbe performed using a second drill bit 100′ according to an embodimentdescribed herein. The second drill bit 100′ can have a differentmacro-shape compared to the first drill bit 100. The second drill bit100′ can have a different configuration of the drill bit core 120compared to the first drill bit 100.

In particular, the second drill bit 100′ may be configured such that thefirst cutting edge is arranged at a maximum of the non-round ornon-circular portion of the drill bit core or arranged so as to becircumferentially spaced from a maximum of the non-round or non-circularportion of the drill bit core in a direction which is opposite to therotation direction in which the second drill bit 100′ is rotated wheninserting it into the osteotomy.

The second drill bit 100′ may be configured such that the first cuttingedge is disposed outside the first compression zone of the drill bitcore.

The method of preparing the osteotomy for receiving an implant can beiterative. For example, the method can proceed from a furthernormalization step, e.g., the second normalizing step 708, to anevaluating step, which may be performed in substantially the same or asimilar manner as the first evaluating step 704, multiple times untilthe normalization is adequate to receive the implant 720.

In particular, in the method illustrated in FIG. 11 , the secondnormalizing step 708 may be followed by a second evaluating step 710 inwhich it is evaluated whether the second drill bit 100′ can be fullyinserted into the osteotomy in the second normalizing step 708. Thesecond evaluating step 710 can be performed in substantially the samemanner as detailed above for the first evaluating step 704.

If the second evaluating step 708 provides a positive result, aninstalling step 712 is performed. In the installing step 712, theimplant 720 is inserted into the osteotomy prepared with the drill bit100′, e.g., in the same manner as detailed above for the installing step706. In the installing step 712, the implant 720 may be inserted intothe jaw bone 730 under the application of an insertion torque in therange of about 35 to 70 Ncm (see FIG. 11 ).

If the second evaluating step 708 provides a negative result, a drillingstep 714 is performed. The drilling step 714 can be performed using adrill bit that has a diameter larger than that of the pilot drill bitused in the pilot step 700. For example, the drill bit used in thedrilling step 714 may have a diameter in the range of 3.4 to 3.9 mm. Thedrill bit used in the drilling step 714 may be a dense bone drill bit.The drilling step 714 can be performed using irrigation. The drill speedin the drilling step 714 can be about 800 rpm.

The drilling step 714 may be followed by another evaluating step (notshown in FIG. 11 ). This further evaluating step may be performed insubstantially the same manner as detailed above for the first evaluatingstep 704.

After the drilling step 714, if the further evaluating step has provideda positive result, an installing step 716 may be performed. In theinstalling step 716, the implant 720 is inserted into the osteotomyprepared in the drilling step 714, e.g., in the same manner as detailedabove for the installing step 706. In the installing step 716, theimplant 720 may be inserted into the jaw bone 730 under the applicationof an insertion torque in the range of about 35 to 70 Ncm (see FIG. 11).

In the first and second normalizing steps 702, 708 detailed above, thethreshold of the torque applied to the first drill bit 100 and thesecond drill bit 100′, respectively, is chosen such that it is smallerthan the torque threshold of the implant 720.

The implant 620 used in the above mentioned methods can be an implant asdescribed in the International Patent Application PCT/EP2017/051953entitled “Dental Implant, Insertion Tool for Dental Implant andCombination of Dental Implant and Insertion Tool”, under Attorney DocketNo. P1542PC00, and filed on the same day as the present application bythe Applicant, Nobel Biocare Services AG, the entirety of thisapplication is hereby expressly incorporated by reference herein inparticular the embodiments of FIGS. 1, 2, 10-12, 13-15, 20 and 21, 34and 35 and related paragraphs of said application are expresslyincorporated by reference herein. Said implant can be a dental implant,comprising: a core body having an apical end, a coronal end, and anouter surface extending along a longitudinal direction between saidapical end and said coronal end; and

-   -   at least one thread extending outwardly from said core body,        wherein said core body comprises    -   a first core shaped zone, in which first core shaped zone the        cross-section of said core body has a number of main directions        in which the radius measuring the distance between the center of        the cross section and its outer contour takes a relative maximum        value and thus a higher value than in neighboring orientations,    -   a core circular zone, in which core circular zone the        cross-section of said core body is basically circularly shaped,        and    -   a core transition zone positioned between said core shaped zone        and said core circular zone, in which core transition zone the        geometry of the cross-section of said core body, as a function        of a parameter characteristic for a coordinate in said        longitudinal direction, changes continuously from a basically        circular shape next to said core circular zone to a shape in        which the cross-section of said core body corresponds to the        shape of the cross section in said core shaped zone.

Said implant can also have a second core shaped zone, in which secondcore shaped zone the cross-section of said core body has a number ofmain directions in which the radius measuring the distance between thecenter of the cross section and its outer contour takes a relativemaximum value and thus a higher value than in neighbouring orientations,and wherein in said first core shaped zone a core eccentricity parameterdefined as the ratio of the maximum radius of the cross section of saidcore body to its minimum radius is larger than in said second coreshaped zone.

Such an implant can also comprise at least one thread extendingoutwardly from said core body, said thread defining a thread outervolume, wherein said thread comprises

-   -   a first thread shaped zone, in which thread shaped zone the        outer cross-section of said thread outer volume has a number of        main directions in which the radius measuring the distance        between the center of the cross section and its outer contour        takes a relative maximum value and thus a higher value than in        neighbouring orientations,    -   a thread circular zone, preferably next to said apical end, in        which thread circular zone the outer cross-section of said        thread outer volume is basically circularly shaped, and        -   a thread transition zone positioned between said thread            shaped zone and said thread circular zone, in which thread            transition zone the geometry of the outer cross-section of            said thread outer volume, as a function of a parameter            characteristic for a coordinate in said longitudinal            direction, changes continuously from a basically circular            shape next to said thread circular zone to a shape in which            the outer cross-section of said thread outer volume            corresponds to the shape of the outer cross section in said            thread shaped zone.

The implant can also comprise a second thread shaped zone in whichsecond thread shaped zone the outer cross-section of said thread outervolume has a number of main directions in which the radius measuring thedistance between the center of the cross section and its outer contourtakes a relative maximum value and thus a higher value than inneighboring orientations,

-   -   wherein in said first thread shaped zone a core eccentricity        parameter defined as the ratio of the maximum radius of the        outer cross section of said thread outer volume to its minimum        radius is larger than in said second core shaped zone.

Such an implant can also have a number of cutting flutes provided atleast in said transition zone.

The dental implant, in particular for insertion into bone tissue of apatient, can also comprise:

-   -   a core body having an apical end, a coronal end, and an outer        surface extending along a longitudinal direction between said        apical end and said coronal end;    -   at least one thread extending outwardly from said core body, and    -   a characteristic implant volume defined by said core body or by        the thread outer volume as defined by said thread, in which for        each value of a parameter characteristic for a coordinate in the        implant's longitudinal direction the cross section of said        characteristic implant volume is characterized by an        eccentricity parameter defined as the ratio of the maximum        distance of the contour of this cross section from its center to        the minimum distance of the contour of this cross section from        its center;        wherein said characteristic volume comprises    -   at least one coronal zone in which said eccentricity parameter        has a maximum, preferably a constant, value, said coronal zone        extending along the implant's longitudinal axis over a coronal        zone length of at least 10% of the total length of the implant;    -   at least one apical zone in which said eccentricity parameter        has a minimum, preferably a constant, value, said apical zone        extending along the implant's longitudinal axis over an apical        zone length of at least 30% of the total length of the implant,        and        at least one transition zone positioned between said coronal        zone and said apical zone in which said eccentricity parameter,        as a function of a parameter characteristic for a coordinate in        said longitudinal direction, changes continuously, preferably in        a linear manner, from a minimum value next to said apical zone        to a maximum value next to said coronal zone, said transition        zone extending along the implant's longitudinal axis over a        transition zone length of at least 10% of the total length of        the implant.

Such a “non round implant” continues, during it insertion in thejawbone, the bone normalization initiated by a drill bit as abovedescribed.

According to another aspect the invention also concerns a kit of partscomprising and a drill bit as above defined and an implant, and inparticular an implant as above defined.

It should be appreciated that certain embodiments and methods describedabove are in the context of dental surgery and forming a hole in apatient's jawbone to receive a dental implant; however, it should beappreciated that certain features and aspects of the embodimentsdescribed herein can also find utility in other surgical applications.For example, certain features and aspects of the embodiments describedherein may be used in a drill configured to form a hole in anotherportion of the body (e.g., bones of the leg, spine, and/or arm) and/or ahole configured to receive a different type of device (e.g., a rod, aspacer, etc.)

It should be emphasized that many variations and modifications may bemade to the herein-described embodiments, the elements of which are tobe understood as being among other acceptable examples. All suchmodifications and variations are intended to be included herein withinthe scope of this disclosure and protected by the following claims.Moreover, any of the steps described herein can be performedsimultaneously or in an order different from the steps as orderedherein. Moreover, as should be apparent, the features and attributes ofthe specific embodiments disclosed herein may be combined in differentways to form additional embodiments, all of which fall within the scopeof the present disclosure.

Conditional language used herein, such as, among others, “can,” “could,”“might,” “may,” “e.g.,” and the like, unless specifically statedotherwise, or otherwise understood within the context as used, isgenerally intended to convey that certain embodiments include, whileother embodiments do not include, certain features, elements and/orstates. Thus, such conditional language is not generally intended toimply that features, elements and/or states are in any way required forone or more embodiments or that one or more embodiments necessarilyinclude logic for deciding, with or without author input or prompting,whether these features, elements and/or states are included or are to beperformed in any particular embodiment.

Moreover, the following terminology may have been used herein. Thesingular forms “a,” “an,” and “the” include plural referents unless thecontext clearly dictates otherwise. Thus, for example, reference to anitem includes reference to one or more items. The term “ones” refers toone, two, or more, and generally applies to the selection of some or allof a quantity. The term “plurality” refers to two or more of an item.The term “about” or “approximately” means that quantities, dimensions,sizes, formulations, parameters, shapes and other characteristics neednot be exact, but may be approximated and/or larger or smaller, asdesired, reflecting acceptable tolerances, conversion factors, roundingoff, measurement error and the like and other factors known to those ofskill in the art. The term “substantially” means that the recitedcharacteristic, parameter, or value need not be achieved exactly, butthat deviations or variations, including for example, tolerances,measurement error, measurement accuracy limitations and other factorsknown to those of skill in the art, may occur in amounts that do notpreclude the effect the characteristic was intended to provide.

Numerical data may be expressed or presented herein in a range format.It is to be understood that such a range format is used merely forconvenience and brevity and thus should be interpreted flexibly toinclude not only the numerical values explicitly recited as the limitsof the range, but also interpreted to include all of the individualnumerical values or sub-ranges encompassed within that range as if eachnumerical value and sub-range is explicitly recited. As an illustration,a numerical range of “about 1 to 5” should be interpreted to include notonly the explicitly recited values of about 1 to about 5, but shouldalso be interpreted to also include individual values and sub-rangeswithin the indicated range. Thus, included in this numerical range areindividual values such as 2, 3 and 4 and sub-ranges such as “about 1 toabout 3,” “about 2 to about 4” and “about 3 to about 5,” “1 to 3,” “2 to4,” “3 to 5,” etc. This same principle applies to ranges reciting onlyone numerical value (e.g., “greater than about 1”) and should applyregardless of the breadth of the range or the characteristics beingdescribed. A plurality of items may be presented in a common list forconvenience. However, these lists should be construed as though eachmember of the list is individually identified as a separate and uniquemember. Thus, no individual member of such list should be construed as ade facto equivalent of any other member of the same list solely based ontheir presentation in a common group without indications to thecontrary. Furthermore, where the terms “and” and “or” are used inconjunction with a list of items, they are to be interpreted broadly, inthat any one or more of the listed items may be used alone or incombination with other listed items. The term “alternatively” refers toselection of one of two or more alternatives, and is not intended tolimit the selection to only those listed alternatives or to only one ofthe listed alternatives at a time, unless the context clearly indicatesotherwise.

What is claimed is:
 1. A method of preparing an osteotomy, the methodcomprising: drilling a hole in a jaw bone with a non-round ornon-circular drill bit; controlling a rotational speed of the non-roundor non-circular drill bit such that a hard bone enters a cutting zone ofthe non-round or non-circular drill bit while the soft bone remains in ano-cutting zone of the non-round or non-circular drill bit while acutting edge positioned within the cutting zone passes by the hard bone,wherein the cutting zone and the no-cutting zone are positioned in thesame cross-sectional plane perpendicular to a longitudinal axis of thenon-round or non-circular drill bit; measuring an insertion torque ofthe non-round or non-circular drill bit; determining the insertiontorque is within an acceptable range; stopping the drilling of thenon-round or non-circular drill bit; and implanting an implant into thehole.
 2. The method of claim 1, further comprising, prior to implantingthe implant into the hole: drilling with a second drill bit to modifythe hole; measuring a second insertion torque of the second drill bit;determining the second insertion torque is within the acceptable range;and stopping the drilling of the second drill bit.
 3. The method ofclaim 1, further comprising forming the hole with a pilot drill bithaving a diameter smaller than the non-round or non-circular drill bit.4. The method of claim 1, further comprising measuring the insertiontorque of the non-round or non-circular drill bit before or until thehole has reached a first predefined length.
 5. The method of claim 4,wherein the first predefined length is indicated by a marking on thenon-round or non-circular drill bit.
 6. The method of claim 4, whereinthe first predefined length is indicated by a removable stop on thenon-round or non-circular drill bit.
 7. The method of claim 1, furthercomprising stopping the drilling of the non-round or non-circular drillbit when the non-round or non-circular drill bit has rotated apredetermined number of turns.
 8. The method of claim 1, wherein thedetermination of the insertion torque comprises sensing an actualinsertion torque of the non-round or non-circular drill bit.
 9. Themethod of claim 1, wherein the determination of the insertion torque iswithin the acceptable range comprises comparing an actual insertiontorque with a desired insertion torque.
 10. The method of claim 1,wherein the rotational speed comprises a rotation time defined by a timeof the cutting edge travelling between a first position to a secondposition, the first position being an initial location of the cuttingedge, the second position being an initial location of a maximum radiusof the non-round or non-circular drill bit.
 11. The method of claim 10,wherein the rotation time is less than a recovery time of the soft bone,the recovery time of the soft bone defined as a time of the soft bonerecovering a radial distance between the maximum radius to the cuttingedge.
 12. The method of claim 10, wherein the rotation time is less thana recovery time of the hard bone, the recovery time of the hard bonedefined as a time of the soft bone recovering a radial distance betweenthe maximum radius to the cutting edge.
 13. A method of preparing anosteotomy, the method comprising: drilling a hole in a jaw bone with anon-round or non-circular drill bit, wherein a cutting edge of thenon-round or non-circular drill bit is at a first radial distance from alongitudinal axis of the non-round or non-circular drill bit, wherein amaximum outer radius of the non-round or non-circular drill bit is at asecond radial distance from the longitudinal axis, wherein the secondradial distance is larger than the first radial distance, wherein thecutting edge and a no-cutting zone are positioned in the samecross-sectional plane perpendicular to the longitudinal axis of thenon-round or non-circular drill bit; measuring an insertion torque ofthe non-round or non-circular drill bit; determining the insertiontorque is not within the acceptable range; and drilling with a seconddrill bit to modify the hole.
 14. The method of claim 13, furthercomprising: measuring a second insertion torque of the second drill bit;determining the second insertion torque is within the acceptable range;stopping the drilling of the second drill bit; and implanting an implantinto the hole.
 15. The method of claim 13, further comprising measuringa second insertion torque of the second drill bit; determining thesecond insertion torque is not within the acceptable range; drilling thehole with a third drill bit; measuring a third insertion torque of thethird drill bit; determining the third insertion torque is within theacceptable range; stopping the drilling of the third drill bit; andimplanting an implant into the hole.
 16. The method of claim 13, furthercomprising: determining the hole has not reached a first predefinedlength; resuming the drilling of the hole with the non-round ornon-circular drill bit until the hole has reached a second predefinedlength.